Cellulose organic ester composition containing an ester of trichloro tertiary-butyl alcohol



Patented Feb. 13, 1934 UNITED STATES PATENT; o ncr.

CELLULOSE ORGANIC ESTER COMPOSITION CONTAINING AN ESTER OF TRICHLOROTERTIARY-BUTYL ALCOHOL No Drawing. Application August 12, 1932 SerialNo. 628,590

Claims.

This invention relates to compositions of matter in which celluloseorganic esters, such as cellulose acetate, are combined or mixed withother substances, such as a compatible plasticizer, with or 5 without acommon solvent or both, and with or without other useful additionagents, so that the resulting product will have properties such as willmake the composition highly advantageous for use in the plastic andanalogous arts, such, for in- 19 stance, as the manufacture of wrappingsheets or tissue, photographic film, molding compounds and products,artificial silk, varnishes or lacquers, coating compositions and thelike.

One object ot this invention is to produce compositions of matter whichmay be made into permanently transparent, strong and flexible sheets orfilms of desired thinness which are substantially waterproof, areunaffected by ordinary photographic fluids and possess the desiredproper- 29 ties of a support for sensitive photographic coatings.Another object of my invention is to produce compositions of matterwhich are capable of easy and convenient manipulation in the plastic andanalogous arts, such as in the manufacture of sheets, films, artificialsilk filaments, varnishes,

lacquers and the like, and to produce compositions which will notinjure, or be injured by, the substances or surfaces with which they areassociated during manufacture. Another object of my invention is toproduce compositions which can be molded at elevated temperatures andhigh pressures to produce plastic products having the desirableproperties of celluloid. Still another object of my invention is toproduce compositions of matter containing cellulose acetate which have ahigh degree of flexibility, softness and pliability. Other objects willbecome apparent to those skilled in the art to which this inventionpertains.

While cellulose acetate has been known for dec- 49 ades, it has alsobeen known that to utilize it in the various plastic arts it isnecessary to mix therewith such plasticizing or conditioning agents astriphenyl phosphate, monochlornaphthalene or the like. Certain of theseand other addition agents are also added for the purpose of reducing theinflammability of the product. Plastic inducing agents, such as thehigher alcohols and their esters, are sometimes also added. Similarly,addition compounds of various kinds have been em- 50 ployed to increaseflexibility, transparency, toughness and other properties which willenhance the value of the resulting product. Addition products for thesame or similar purposes are also added to cellulose acetate to prepareit for use in the other plastic arts, such as in the manufacture oflacquers, varnishes, artificial silk filaments, molded compounds and thelike. While the plasticizers or other addition agents heretoforediscovered have had their utility in the art, the increasing use towhich cellulose acetate has been put and the increasing number ofdesirable properties required of cellulose acetate for most purposeshave made the discovery of new and economical plasticizers or otheraddition agents a matter of considerable importance to the art. This hasbeen a problem of some difficulty, since many of the Intro-cellulosesolvents are not solvents for cellulose acetate, and many substanceswhich act as plasticizers for nitro-cellulose are not suflicientlycompatible with cellulose acetate to be used as plasticizers incellulose acetate compositions.

I have discovered that valuable properties may be induced in and/orcontributed to compositions containing organic esters of cellulose, suchas cellulose acetate, by adding thereto as a plasticizing compound anester of trichloro tertiarybutyl alcohol, such as the acetate, benzoate,phthalate, succinate or lactate of trichloro tertiary-butyl alcohol. Theparticularly useful 89 properties which these compounds induce in orcontribute to cellulosic compositions containing them are hereinafterenumerated.

The acetate and the benzoate of trichloro tertiary-butyl alcohol havebeen described in the 7 literature. The lactate, succinate and phthalateof trichloro tertiary-butyl alcohol may be prepared as follows. 500grams of trichloro tertiarybutyl alcohol is placed in a 3-liter flask,together with about 1.5 gram molecular Weights of the' acidcorresponding to the ester to be prepared, about 25 cc. of concentratedhydrochloric acid, and about 500 g. of xylene. In the" case of thephthalate, phthalic anhydride is used in place of phthalic acid. Xylene,together with the water present in the starting materials and thatformed by the esterification, is slowly distilled off through a 1.5-footfractionating column. The xylene is separated from the Water andreturned to the distilling flask, and the process is re- 1 peated untilno more water comes over. The product remaining in the distilling flaskis then fractionated. In the case of trichloro tertiarybutyl lactatethis fractionation should take place under diminished pressure.Trichloro tertiary- 0 butyl phthalate boils at 155 C. Trichlorotertiary-butyl succinate boils at 148,153 C. Trichloro tertiary-butyllactate boils at 67-72" C. at 58 mm. pressure.

In order that those skilled in this art may bet-1 ter understand myinvention I would state, by

way of illustration, that for the manufacture of photographic film orother sheets my new compositions of matter may be compounded as fol- 5lows: 100 parts of acetone-soluble cellulose acetate, i. e. celluloseacetate containing from 36% a to 42% acetyl radical, approximately, isdissolved with stirring at atmospheric temperature in 300 to 500 parts,preferably 400 parts, by weight, of acetone. To this solution may beadded from to 50 parts by weight of trichloro tertiarybutyl acetate,phthalate, or succinate, or from 10 to 30 parts by weight of trichlorotertiarybutyl benzoate or lactate. Within the limits 5 stated, theamount of plasticizer may be decreased or increased, depending uponwhether it is desired to decrease or increase, respectively, theproperties which these plasticizers contribute to the finished product.The amount of solvent employed may also be increased or decreased,depending upon whether it is desired to have a more or less freelyflowing composition, respectively.

A composition of matter prepared as above described may be depositedupon any suitable film-forming surface to form a film or sheet, in amanner well known to those skilled in the art. A film so produced haspermanently brilliant transparency and very low infiammability, burningeven less readily than ordinary newsprint. Films or sheets produced inaccordance with my invention are tough and flexible. For instance, filmsof cellulose acetate plasticized with from 10% to 50% (parts by weightbased on the cellulose acetate) of trichloro tertiarybutyl succinate hadan initial flexibility of from 65% to 265% greater than that of filmcontaining no plasticizer, and films containing from to 50% of trichlorotertiary-butyl phthalate m had an initial flexibility of from 100% to235% greater than that of film containing no plasticizer. Furthermore,film so plasticized maintains flexibility in a superior fashion. Forinstance, films containing from .10 to 50% of trichloro tertiary-butylacetate or from 20 to 30% of trichloro tertiary-butyl benzoatemaintained flexibility at 65C. for over 242 days, and films containingfrom 30 to 50% of trichloro tertiary-butyl phthalate or succinate or 30%of trichloro tertiary-butyl lactate maintained flexibility at 65 C. forover 100 days, whereas an unplasticised film became brittle in 30 days.This indicates that films so plasticized will withstand ordinary usagesatisfactorily for many years.

Other similar solvents (instead of acetone) which are compatible withthecellulose acetate and my new plasticizers will also occur to thoseskilled in this art, such as ethylene chloridealcohol mixtures. In likemanner these plastifig cizers may be compounded with other single or-'ganic esters of cellulose, such as cellulose propionate,butyratastearate and the like,or with mixed organic esters, such ascellulose aceto-stearate, cellulose aceto-propionate, celluloseaceto-butyrate, cellulose aceto-lactate, cellulose aceto-tartrate or thelike, a suitable solvent which will dissolve both the cellulosicderivative and the plasticizer being employed, such, for instance, as analkylene chloride with or Without the addition of alcohol.

Inasmuch as my above-described compositions of matter are useful in theproduction of films and sheets, it will be apparent that my newplasticizers may also be employed with advantage in the other branchesof the plastic art. For instance, my above-described compositions ofmatter may be employed in the manufacture of artificial silk by the dryspinning method. With the proper coagulating bath they may also beemployed for wet spinning. My novel plasticizers may also be employedwith advantage in connection with a number of the known lacquer andvarnish formulae with which they may be found to be compatible. In suchcases the plasticizer is usually first put into solution in thecellulose derivative solution, and if non-solvents are added for thepurpose of cheapening the composition they are added only to such anextent as will not precipitate the derivative from solution.

Other uses within the scope of my invention will also suggest themselvesto those skilled in the art and are to be included within the scope ofthe claims appended hereto.

The esters of trichloro tertiary-butyl alcohol may also beadvantageously used as plasticizers in cellulose acetate moldingcompositions. For instance, when about 30% (parts by weight based on thecellulose acetate) of the acetate, benzoate, phthalate, succinate orlactate of trichloro tertiary-butyl alcohol is homogeneously mixed withcellulose acetate, the mixture may be converted into a hard, transparentor translucent plastic product by molding at a temperature of 140- 180C. and a pressure of 2500 to 4000 pounds per square inch for a period offrom 2 to 5 minutes, 10 in a manner already known to those skilled inmolding compounds of that nature. In the case of trichlorotertiary-butyl benzoate, a temperature of 180 C. is required formolding.

Moreover, I have found that, upon the addition to cellulose acetate ofapproximately of trichloro tertiary-butyl acetate, succinate, orphthalate, quite unexpected compatibility of the plasticizer with thecellulose acetate exists and also that quite unexpected flexibility,plasticity 5 and clarity of the final product result. Contrary toexperience in most cases where such a large proportion of plasticizer isused, no exudation or crystallizing out of the plasticizer occurs.Compositions containing approximately 100% of 12 trichlorotertiary-butyl acetate, succinate or phthalate have great utility wherea highly flexible compound is desired, such as in the coatin of a base(for instance, cloth or other fabric) in the production of artificialleather, or in the 5 production of relatively thin sheets wherein morethan the usual flexibility is important. Such a composition, ifconverted, for instance, into sheet form will be found to be supple andnon-rigid, and to have the ability to conform readily to a surface uponwhich it may be placed, and this even at atmospheric temperatures.

These novel compositions of matter are produced by merely mixing theplasticizer with cellulose acetate and then adding sufilcient of acommonsolvent, such as acetone, whereupon an intimate mixture of theplasticizer with the cellulose acetate results. The amount of acetone orother common solvent to be employed varies, of course, within ratherwide limits depending upon the fluidity of the composition desired. 100parts of acetone will sufiice for many purposes, although we prefer touse 400 parts. Various high boilers or evaporation retardents, such asethyl lactate, amyl acetate or the like may also be added if desired, asis well known in this art.

The compositions of matter so produced may then be coated into sheets inthe usual way by depositing them upon plates or rolls and permitting thesolvent to evaporate. If my novel compositions are to be employed in themanufacture of artificial leather, they may be coated upon, forinstance, a cloth support and the solvent permitted to evaporate, or thecloth support may be caused to pass through the celluloseacetate-plasticizer composition and permitted to absorb the solution,the solvent in the coating being then permitted to evaporate. In eithercase, the solvent may, of course, be recovered if desired by condensingthe vapors, etc.

While above and in certain of the claims appended hereto, I havereferred tothe use of a plasticizer in approximately equal proportions,namely in a ratio of approximately 100%, it will be understood thatwithin this terminology variations of from 10% to 15% less than 100% ofplasticizer and as much as 25% to 50% more than 100% of the plasticizermay in some instances be desirable.

What I claim as my invention and desire to be secured by Letters Patentof the United States 1. A composition of matter comprising a celluloseorganic ester and an ester of trichloro tertiary-butyl alcohol.

2. A composition of matter comprising cellulose acetate and an ester oftrichloro tertiarybutyl alcohol.

3. A composition of matter comprising cellulose acetate and trichlorotertiary-butyl acetate.

4. A composition of matter comprising cellulose acetate and trichlorotertiary-butyl succinate.

5. A composition of matter comprising cellulose acetate and trichlorotertiary-butyl phthalate.

6. A composition of matter comprising 100 parts of cellulose'acetate andabout 10 to 100 parts, by weight, of trichloro tertiary-butyl acetate.

7. A composition of matter comprising 100 parts of cellulose acetate andabout 10 to 100 parts; by weight of trichloro tertiary-butyl succinate.

8. A composition of matter comprising 100 parts of cellulose acetate andabout 10 to 100 parts, by weight, of trichloro tertiary-butyl phthalate.

9. A transparent, flexible sheet comprising 100 parts of celluloseacetate and about 10 to 30 parts of an ester of trichloro tertiary-butylalcohol.

10. A molding composition adapted for molding under elevatedtemperatures and high pressures, comprising cellulose acetate and anester of trichloro tertiary-butyl alcohol.

HENRY B. SlVIITH.

